Electric clock



Sept. 2, 1941.

J. E. ESHBAUGH ET AL,

ELECTRIC CLOCK Filed March 13, 1939 ZSnventors 6556 6 6511% uglz & Warm/d 5W. Wazzaolyh y Gttomegs Patented Sept. 2, 1941 UNITED STATES PATENT OFFICE ELECTRIC CLOCK ware Application March 13, 1939, Serial No. 261,492

13 Claims.

This invention relates to oscillating mechanisms, particularly to means for starting and maintaining the oscillation thereof.

Conventional apparatus of this type employs the use of mechanical devices for imparting impulses either directly to the oscillating device or to other mechanism mechanically connected thereto. In some mechanisms of this type electrical control means are employed which use electrical breakers to interrupt an electrical circuit through an electromagnet operating mechanical linkage means for imparting impulses to the oscillating device. All of the above devices are subject to wear due to friction, and the electrical breakers particularly are found to be unreliable on account of the pitting and burning of the contact points due to arcing which increases the resistance across these points and makes it necessary to replace them.

In the present invention frictionless means are provided which will operate indefinitely on a low voltage source to impart magnetic impulses directly to the oscillating member by controlling the current through an electromagnet by means of a thermionic tube the characteristics of which are altered by the movement of the oscillating member located in a spaced relation with respect to the tube.

This invention is particularly adaptable to clock mechanisms regulated by either a balance wheel or pendulum.

One of the objects of this invention is to provide a frictionless control and driving mechanism for imparting impulses to any oscillating members of the type described at a point in the cycle when its angular velocity is increasing and in either direction of movement so that the member will continue to oscillate at its natural period. It has been found that when the impulses are phased in this manner the disturbing effect on the oscillating member will be negligible.

With these and other objects in view, the embodiments of our invention will be best understood by reference tothe following specification and claims and illustrated in the accompanying drawing in which:

Figure 1 is a plan view of our driving and control mechanism.

Figure 2 is a plan view taken substantially on the line 22 of Figure 3 with some of the parts shown in section and broken away to show structural details.

Figure 3 is a side elevation of the structure shown in Figures 1 and 2 with some of the parts broken away to show other details, and,

Figure 4 is a wiring diagram showing the electrical connections extending between the various elements of the mechanism.

Referring to Figures 1 to 3, the control and 5 driving mechanism is supportedJn a frame comprising a lower plate I, an upper plate 3, and a bifurcated plate 5. The upper plate 3 rests on the bifurcated plate 5 and these plates are provided with spaced holes indicated at 1 through which threaded studs 9 extend. The lower ends of the studs 9 are riveted to the lower plate and spacing tubes II are placed over the studs 9 in order to support the plates 3 and 5 in a vertical spaced relation with respect to the lower plate I.

The assembly is held firmly in this relation by means of nuts I3 threaded on the upper ends of the studs 9.

A balance staff I5 having end portions of re duced diameter is supported for oscillatory movement in aligned pivot bearings I! and I9 in the plates I and 3 respectively. A balance wheel 2| is fixed to the balance staff I5 intermediate its ends and a soft iron armature 23 is also fixed to the staff immediately above the balance wheel 25 and a permanent magnet armature 25 is fixed to the staff immediately below the wheel. The armatures 23 and 25 are of bar form and extend outwardly at right angles to the staff in diametrically opposite directions.

The balance staff assembly is biased by a hair spring 21 having one end 29 fixed to the staff and the other end 3| fixed to a downwardly extending portion 33 of the adjusting lever 35. The lever 35 is frictionally supported in a bearing in the 35 upper plate 3 and is located in axial alignment The length of the hair spring is fixed with the type mounting shown, its length being selected to obtain the desired period of oscillation of the balance staff assembly. The lever 35 serves only to adjust the angular position of the balance 4 staff assembly with respect to the frame I.

The bifurcated plate 5, previously referred to, is provided with integral formed ears 39 which are bent downwardly to act as a clip embracing a two-element caesium argon electronic tube 4| and support this tube in a horizontal plane extending through the horizontal centerline of the permanent magnet armature 25 and in a spaced horizontal relationship with respect to the end of this armature.

An electromagnet 43 is located on the opposite side of the balance stafi diametrically opposite the tube 4|. A right angle bracket 45 bolted at 41 to the lower plate and to the magnet core as indicated at 49 serves to support this magnet in a horizontal plane extending through the horizontal centerline of the soft iron armature and in spaced horizontal relationship with the outer end thereof.

The tube 4| comprises two elements: a heated cathode 5| and a plate 53, as best shown in Figure 4. The tube contains caesium and argon vapor which has been found capable of causing a discharge between the tube elements when the cathode is connected to a very low voltage source. It has been further found that the discharge may be controlled by a weak magnetic field applied to a space adjacent the electrodes which distorts the path of the electron flow between them. When this weak field is present the current passing through the tube will be greatly decreased and when removed the current will be increased to its maximum value. The magnetic field for controlling the current in the present instance is derived from the permanent magnet armature 5 and the value of the current depends upon its position with respect to the tube 4|. When the permanent magnet 25 is in close proximity to the tube 4|, as shown in the full lines in Figure the current in the plate circuit is minimum, and conversely when the permanent magnet 25 is in the position indicated by the dotted lines, the current is maximum.

In order to control the current through the electromagnet by the thermionic tube so that an impulse is imparted to the balance wheel each time it is moving toward its neutral position from either direction at which time its velocity is increasing so that the wheel will be started and continuously oscillated at its natural frequency with minimum disturbance, the following circuit connections are employed as best shown in Figure 4.

The heated cathode 5| is connected directly across a low voltage battery 55 by conductors 51 and 59 and one side of the electromagnet 43 is connected to the plate 53 by a conductor 63 while the other side is connected to the conductor 59 by a conductor 6|. These connections provide a means of controlling the current to the electromagnet 43 through the tube 4|.

The operation of the driving mechanism is as follows: With the parts in the position shown by the full lines in Figures 2 and 4, the permanent magnet 25 is in close proximity to the tube 4| and the current flowing through the electromagnet 43 is minimum and accordingly the pull exerted on the soft iron armature 23 by the electromagnet is minimum. When the balance stafi assembly, which includes the balance wheel 2|, soft iron armature 23 and permanent magnet armature 25, is in either of the positions iridicated by the dotted lines on either side of the neutral or full line position, the current flowing relative air gap distance between them. This force is applied to the balance staff assembly each time its angular velocity is increasing and when once oscillating will continue to do so indefinitely.

The mechanism may be made self starting by rotating the balance stair assembly by means of the adjusting lever 35 through an angle of approximately 15 degrees. The armatures 23 and 25 will then be moved angularly 15 degrees from the position in which they are shown in Figure 2. When in this position with the battery connected to the tube 4| and electromagnet 43 as shown. an initial torque impulse will be imparted to the armature 23 by the electromagnet 43 which will start oscillation of the balance stall assembly.

It is evident that this oscillating movement may be imparted to a pendulum with similar results and that any well-known means for changing oscillatory movement to angular may be employed in combination with suitable gearing for moving the hands of a chronometer or the like. These mechanisms are well-known to the art and may be included in a unitary frame but in this instance only the driving'mechanism has been shown.

We claim:

1. In a device of the type described, a thermionic tube having spaced electrodes, means for applying a potential across said electrodes to cause an electron flow, movable magnetic means located in juxtaposition to the tube whereby its position affects the electron flow, and an electromagnet supplied with current through said tube and located adjacent said magnetic means to cause movement thereof by changes in the magnetic strength caused by variations in the electron flow whereby periodic impulses are imparted to the movable magnetic means.

2. In a device of the type described, a thermionic tube having spaced electrodes. means for applying a potential across said electrodes to cause an electron flow, vibrating magnetic means located in juxtaposition to the tube whereby its position affects the electron flow, and an electromagnet supplied with current through the tube and located adjacent the magnetic means to cause movement thereof by changes in the magnetic strength caused by the variations in the electron flow whereby periodic impulses are imparted to the vibrating magnetic means.

3. In a device of the type described. a thermionic tube having spaced electrodes, means for applying a potential across said electrodes to cause an electron flow, a resiliently restrained vibrating magnetic means located in juxtaposition to the tube whereby its position affects the electron flow, and an electromagnet supplied with current through the tube and located adjacent the magnetic means to cause movement thereof by changes in the magnetic strength caused by the variations in the electron flow whereby periodic impulses are imparted to the vibrating magnetic means.

4. In a device of the type described, a thermionic tube having spaced electrodes in a vapor containing caesium and argon, means for applying a low voltage potential across said electrodes to cause an electron flow, movable magnetic means located in juxtaposition to the tube wherebly its position afiects the electron flow, and an electromagnet supplied with current through said tube and located adjacent said magnetic means to cause movement thereof by changes in the magnet strength caused by variations in the electron flow whereby periodic impulses are imparted to the movable means.

5. In a device of the type-described, a source of low voltage, a two-element thermionic tube connected to the source so that an electron flow is established between these elements, magnetic means for modifying the electron flow, and an electromagnet connected both to the source and one of the tube elements so that variations in the electron flow through the tube causes variations in the excitation current in the electromagnet which varies the magnetic attraction between the electromagnet and the magnetic means so that the attraction decreases as the magneticmeans is moved toward said :tube and increases as it is removed from said tube.

6. In a device of the type described, magnetizable means supported for oscillatory movement, a thermionic tube having spaced electrodes, an electromagnet, said tube and said electromagnet being located in juxtaposition with said magnetizable means, and conducting means for applying a potential across said electrodes for causing an electron flow therebetween and connecting the electromagnet to one element of the tube and the source of potential so that current will flow through said electromagnet to attract said magnetizable means and impart an impulse tending to move said magnetizable means toward the tube and electromagnet so that the electron flow will be again modified to decrease the current and attraction between the electromagnet and the magnetizable means upon an approach of the magnetizable means toward the tube and electromagnet and conversely to modify the electron flow so that the current and attraction between the electromagnet and magnetizable means will increase when the magnetizable means moves away from the tube and-electromagnet, thus setting up oscillatory movement of the magnetizable means.-

'7. In a thermionic impulse generator compris ing a thermionic tube having spaced electrodes, means for applying a source of potential across said electrodes for causing an electron flow in a definite path therebetween, vibrating magnetic means arranged to approach and leave a point adjacent said electrodes periodically and thereby distort the -path of electron flow, and an electromagnet adjacent said vibrating magnetic means connected in circuit with said tube and source and supplied with current from said source, the phase and value of which is controlled by the path of electron flow through said tube whereby the vibrating magnetic means is periodically attracted by the electromagnet to maintain vibratory motion.

8. In a device of the type described, a thermionic tube having spaced electrodes, means for applying a potential across said electrodes for causing electron flow, a vibrating member, magnetic means associated with said member and movable thereby, said magnetic means being located in juxtaposition to the tube whereby its relative position with respect to the tube affects the electron flow therethrough, and an electromagnet supplied with current from the source of potential controlled by the electron flow through the tube and located adjacent to the magnetic means to cause movement thereof by changes in the magnetic strength of the electromagnet caused by variations-in the electron flow whereby periodic impulses are imparted to the vibrating member.

9. In a device of the type described, a thermionic tube having spaced electrodes, means for applying a potential across said electrodes for causing electron flow, a resiliently restrained member oscillating at its natural frequency, permanent magnet means associated with and moved by said member through an angle on either side of and in the plane of the tube whereby the electron flow is greatly distorted when the permanent magnet is adjacent the tube, an electromagnet .supplied by current through the tube and an armature displaced angularly with respect to the permanent magnet and moved by said member through an angle on either side of and in the plane of the electromagnet so that the attraction between them will be inversely proportional to the square of the distance between them and proportional to the current through the tube whereby periodic impulses are imparted to the armature on either side of its mean position and the oscillation of the member maintained.

10. In a mechanism for imparting impulses to an oscillating member comprising, a resiliently restrained member oscillating at its natural frequency, a thermionic tube having spaced electrodes, an electromagnet, a source of current connected across the electrodes of the tube for causing an electron flow in a definite path between the electrodes, means connecting said electromagnet to said source and one tube element, a bar magnet fixed radially with respect to the member which is arranged to oscillate in an arc of a circle past the tube, thus modifying the path of the electron flow and current to the electromagnet, depending upon its position with respect to said tube which is located in the plane of this movement and slightly displaced with respect to the center of the arc of movement, and a bar armature also fixed radially with respect to the oscillating member and angularly displaced with reference to the bar magnet, said armature being moved in the plane of the electromagnet by periodic impulses imparted to it by the current in said electromagnet caused by the changes in the electron flow due to the move ment of the bar magnet.

11. In a device of the type described comprising a supporting frame, a balance wheel assembly having a permanent magnet and an armature supported thereon, bearings on said frame supporting said assembly for oscillatory movement therein, resilient means connected between said balance wheel assembly and said frame to restrain movement of said assembly, a thermionic tube having spaced electrodes, an electromagnet, said tube and electromagnet located on said frame adjacent the path of movement of the permanent magnet and armature respectively and slightly displaced from the center of the maximum angle of movement of the said magnet and armature, means for applying a source of potential across the electrodes of said tube and said electromagnet so that the current to the electromagnet is controlled by the elec- -tron flow across the tube electrodes which is periodically distorted by the vibrating permanent magnet and the resulting magnetic impulses imparted to the armature are so phased that oscillatory movement is imparted to the balance wheel assembly.

12. In a device of the type described, bearings, a vertical shaft movably supported in said bearings, magnetizable means movable with said shaft and extending outwardly therefrom, a thermionic tube having spaced electrodes, an

electromagnet, said tube and said electromagnet being located in juxtaposition to said magnetizable means, a source of electrical energy, means for connecting said source to said electrodes for causing an electron flow therebetween and means connected the electromagnet through to said tube and said source so that current will flow through the electromagnet and thus attract the magnetizable means when it is angularly displaced from the electromagnet, moving it closer to the tube whereby the path of the electron flow will be distorted by the magnetizable means and the current fiow to the electromagnet will be reduced.

13. In a device of the type described, a thermionic tube having spaced electrodes, a source of electrical energy connected across said electrodes for causing electron flow, a member oscillating at its natural frequency in a horizontal plane about a vertical axis, resilient means to restrain oscillatory movement of said member, a bar magnet supported in a radial relation with respect to the vertical axis on said member and movable thereby through an angle on either side of and in a planeextending through the space between the electrodes of the tube whereby the electron flow is distorted when the magnet is adiacent said tube, an electromagnet connected to said source and to one tube electrode and being supplied with current through said tube, and an armature supported in a radial relation with respect to said vertical axis on said memher, said armature movable through an angle on either side of and in the plane of the electromagnet by being attracted to said electromagnet when it is energized by current from said tube when the electron flow therein is least distorted so that attraction force between said armature and said electromagnet will be inversely proportional to the distance separating them and proportional to the current through the tube whereby impulses are imparted to the armature on either side of its mean position and the oscillation of the member will be thereby maintained.

JESSE E. ESHBAUGH. DONALD W. RANDOLPH.

CERTIFICATE OF CORRECTION. Patent No. 2,25LL1LF76- September 2, 19in.

JESSE E. ESHBAUGH, ET AL.

It is hereby certified that error appears-in the printedspecification of the above numbered patent requiring correction as follows: Pageh, first column, line 6, claim 12, for the words "connected the electronngnet through to" read connecting the electromggnet-to--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 2nd day of December, A. D. 1914.1.

- Henry Ven Arsdale, '(Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTIOK. Y Patent No. 2,25 h L76- September 2, 1914.1.

JESSE E. ESHBAUGH, ET AL.

It is hereby certified that error appears-in the printed epecification of the above numbered patent requiring correction as follows: Pageh, first column, line 6, claim 12, for the words "connected the electromgnet through to" read --connecting the electromegnet'to-q and that the said Letters Patent should be read with this correction therein that the same muy conform to the record of'the case in the Patent Office.

Signed and sealed this 2nd day of December, A. D. 19in.

- Henry Van Arsdal'e, '(Seal) Acting Commissioner of Patents. 

